1. Field of the Invention
The present invention relates to a rotary engine in which a cylindrical-shaped flywheel rotor is placed inside a cylinder.
2. Description of the Related Art
Conventionally, a rotary engine, in which a triangular-shaped rotor is placed inside a cylindrical-shaped cylinder with the three vertices of the rotor coming in contact with the inner wall of the cylinder as the rotor turns, has been known. However, in this kind of rotary engine, since the three vertices of the rotor come in frictional contact with the inner wall of the cylinder, there is a problem in that energy loss due to friction, durability and fuel efficiency of the engine become worse than in than in the case of a reciprocating engine, as well as construction is complicated making it difficult to produce.
Therefore, the inventors of the present invention have invented several flywheel engines in which a cylindrical-shaped flywheel rotor is placed inside a cylindrical-shaped cylinder, with a circular space being formed between the rotor and inner wall of the cylinder; for example one such invention is an engine having a floating-type piston head that is provided on the outer perimeter of the rotor and that is capable of moving into contact with or moving away from the inner wall of the cylinder (see WO/JP2007/099634).
This proposed rotary engine brings fuel mixed with air into the circular space during the first rotation of the rotor, while at the same time, a piston head pushes exhaust gas that occurred during the previous combustion of fuel, and discharges that exhaust gas through an exhaust valve from the circular space into an exhaust pipe. During the second rotation of the rotor, with the circular space blocked on the downstream side in the rotational direction of the rotor near the combustion chamber, the rotary engine compresses the fuel with the piston head until it is close to the combustion chamber, then blocks the circular space on the upstream side in the rotation direction of the rotor near the combustion chamber, while at the same time causing the piston head to move back from the rotor and then stick out again, feeding the compressed fuel to the rear surface side of the floater. During the third rotation of the rotor, at the instant that the piston head passes the combustion chamber, the spark plug ignites the fuel and causes explosive combustion, and this explosive combustion of the fuel on the rear surface side of the piston head generates a propulsion force. By going through each of the processes, intake-exhaust, compression and explosive combustion, a rotational output is obtained in the output shaft of the rotor.
The proposed rotary engine described above has the advantage in that it is possible to obtain a large force even with a small explosive force, as well as obtain good durability with little friction loss along the inner wall of the cylinder. However, the piston head of the rotor is made such that it is movable, so there is a problem in that construction is complicated.